Crop Factor Calculator

Calculate crop factor and equivalent focal length based on sensor size.

Equivalent Focal Length

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Crop Factor —

Crop Factor Information

Crop factor is the ratio of field of view change based on sensor size. Smaller sensors have narrower angle of view compared to full frame.

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Definition and Concept of Crop Factor

Crop Factor represents the field of view ratio based on camera sensor size. Full frame (36×24mm) is the reference (1.0x), smaller sensors have narrower field of view. APS-C Canon 1.6x makes a 50mm lens work like 80mm on full frame, APS-C Nikon/Sony 1.5x works like 75mm. Micro Four Thirds 2.0x makes a 25mm lens look like 50mm, 1-inch sensor 2.7x is used in premium compact cameras. Smaller sensors have a telephoto advantage for wildlife/sports photography, but wide-angle is difficult.

Equivalent Focal Length Calculation

Equivalent focal length = Actual focal length × Crop factor. Example: APS-C Canon (1.6x) with a 50mm lens → 50 × 1.6 = 80mm equivalent. Nikon APS-C (1.5x) with a 35mm lens → 35 × 1.5 = 52.5mm standard view. Micro Four Thirds (2.0x) with a 12-35mm zoom → 24-70mm equivalent. 1-inch sensor (2.7x) with a 10mm lens → 10 × 2.7 = 27mm equivalent. Portrait: For an 85mm effect on APS-C, use 85 ÷ 1.6 = 53mm lens (or 50mm).

Sensor Type Characteristics

Full Frame (1.0x): Canon EOS R5, Nikon Z9, Sony A7 series. Pros: wide angle, excellent low-light, shallow depth. Cons: expensive, heavy. For landscape/portrait professionals. APS-C Canon (1.6x): EOS R7, EOS 90D. Pros: telephoto effect (70-200mm → 112-320mm), affordable. Cons: limited wide-angle. Good for wildlife/sports. APS-C Nikon/Sony (1.5x): Z50, α6400, slightly wider than Canon, a balanced choice. Micro Four Thirds (2.0x): Olympus OM-1, Panasonic GH6, lightweight and video-focused. 1-inch (2.7x): Sony RX100, Canon G7X.

Lens Selection Strategy

Standard view (50mm equiv): Full frame 50mm, APS-C Canon 31mm (or 35mm), APS-C Nikon 33mm (or 35mm), Micro Four Thirds 25mm. Wide angle (24mm equiv): Full frame 24mm, APS-C Canon 15mm, APS-C Nikon 16mm, Micro Four Thirds 12mm. Telephoto (200mm equiv): Full frame 200mm, APS-C Canon 125mm (or 135mm), Micro Four Thirds 100mm. Portrait (85mm equiv): Full frame 85mm, APS-C Canon 50mm, Micro Four Thirds 42.5mm (or 45mm). All-purpose zoom: Full frame 24-70mm = APS-C Canon 15-45mm = Micro Four Thirds 12-35mm.

Depth of Field and Bokeh

Crop factor affects depth of field. At the same field of view and aperture, smaller sensors have deeper depth. Example: To match full frame 50mm f/1.8 on APS-C (1.6x), you need 31mm f/1.1, but such lenses are rare. Full frame 85mm f/1.8 portrait lens effect on APS-C Canon requires 50mm f/1.1, but in practice use 50mm f/1.4 or 56mm f/1.4. Micro Four Thirds 25mm f/1.4 is 50mm equivalent but depth equals full frame 50mm f/2.8. Full frame has an advantage in shallow depth/background blur (bokeh).

Real-World Shooting Scenarios

Landscape: Need wide angle → Full frame + 16-35mm or APS-C + 10-24mm. Micro Four Thirds 7-14mm (14-28mm equiv) provides ultra-wide. Portrait: Shallow depth + 85mm view → Full frame 85mm f/1.4 optimal; APS-C 50mm f/1.4 alternative but depth differs. Wildlife: Telephoto advantage → APS-C + 100-400mm = 640mm equiv, cheaper and lighter than full frame 600mm. Sports: APS-C 1.6x makes 70-200mm → 320mm telephoto. Travel: Lightweight important → Micro Four Thirds 12-100mm (24-200mm equiv) all-in-one lens.